The goal of this Center is to develop and improve techniques for identification of arboviruses and similar viruses through the world; to assist in the diagnosis of disease outbreaks; and to uncover prevalence of infection by these agents through seroepidemiological surveys. The proposed work for the term of this grant is: 1) Identification of from 50 to 70 viral strains, in addition to precise biochemical characterization of orbiviruses in the Changuinola and Palyam serogroups; 2) investigation of serological relationships between Rift Valley fever and the phlebotomus fever serogroup; 3) more precise analyses of the antigenic relationships in the Nairovirus supergroup, particularly by the reduction of fluorescent foci of infection test; 4) seroepidemiological survey for arbovirus activity in Sudan with special stress on the phlebotomus fever antigenic group; 5) an extensive seroepidemiological survey for the presence of antibodies against Lassa, Marburg, Ebola and Congo-Crimean hemorrhagic fever viruses in Senegal, Ghana, Liberia, Nigeria and Sudan will be initiated; this project will be funded in great part by other sources; 6) continued efforts will be made to improve early diagnosis of arbovirus disease, mainly through the use of IF and ELISA tests; 7) distribution of reagents to qualified laboratories.